1. Field of the Invention
The present invention is directed to a metal-oxide-semiconductor (MOS) component.
2. Description of the Prior Art
MOS components are known in the art having the general arrangement of at least one drain zone, at least one base zone, and at least one source zone arranged in the base zone. At least one gate electrode in such known structures is arranged over the drain zone, and is electrically insulated from the source zone and from the drain zone. A source electrode at least partially covers the source-side surface of the semiconductor body, the source electrode being conductively connected to the source zone and to the base zone, and being electrically insulated from the gate electrode. Such MOS components form, for example a MOSFET.
MOSFETs have a unipolar conduction mechanism which carries the current to a prescribed limit of the field strength. When the voltage in the semiconductor body increases, charge carrier pairs arise and the minority charge carriers are extracted to the source electrode by the electrical field. The minority charge carriers flow partially laterally along the source zone. When the voltage at the pn-junction between the source zone and the base zone increases to approximately 0.5 volts, the source zone begins to emit electrons. This results in an increase in the current density, and may possibly result in the activation of a parasitic bipolar transistor, composed of the source zone, the base zone and the drain zone. The current density in the drain zone is caused to suddenly increase upon the activation of such a parasitic bipolar transistor, and the MOSFET is destroyed by so-called second breakdown. The destruction mechanism is similar in an IGBT; the application of current to the anode-side bipolar transistor produces additional holes which can result in a latch-up of the parasitic thyristor.